NASA studies twins to see what happens to astronaut DNA in space

What happens to our DNA, RNA and proteins if we spend a long time in space? A pair of 50-year-old twins will help NASA find out.

Identical twins Mark and Scott Kelly have signed up to be part of the first-ever twin study that takes place, at least partially, in space.

In March 2015, veteran astronaut Scott Kelly will begin a one-year stint living aboard the International Space Station. It will be the longest amount of consecutive time that any American astronaut has spent in space.

His brother Mark Kelly, who is married to former Arizona Rep. Gabrielle Giffords, will stay on Earth and serve as a control in the study.